A circuit layout includes one or more standard cells which correspond to active devices having a specific functionality. Cells for active devices which are routinely repeated are often included in a cell library. These cells are called standard cells in some instances. Cells include pins, which are used to convey signals into and out of the cell. At least one pin of a cell is connected to a pin of at least one other cell in order to transfer signals between the various cells. Routing lines are provided to interconnect the pins of various cells to facilitate signal transfer between different cells to provide a desired functionality for the circuit layout.
As technology nodes decrease, flexibility for routing lines is decreased due to smaller distances between cells and between elements within cells. For example, at technology nodes of 10 nanometers or less, at least one metal level includes routing lines extending only in a single direction. This routing scheme is called one-dimensional routing in some embodiments. A metal level is a layer of conductive lines in a plane having a nearly uniform distance from a substrate. Global connections are routing lines which extend across one or more standard cells. In some instances, global connections extend across an entirety of the circuit layout. Global connections only extend in one direction for circuit layouts which include one-dimensional routing.